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Project title

Evaluation of models (PaSim, RothC, CENTURY, DNDC) for simulation of grassland carbon cycling at plot, field and regional scale

Primary Funding Agency

Environmental Protection Agency

Co-Funding Organisation(s)

n/a

Lead Organisation

University College Cork (UCC)

Lead Applicant

Kenneth Byrne

Project Abstract

Biogeochemical models are increasingly used to simulate GHG exchange and carbon cycling in terrestrial ecosystems. Models enable the integration of processes and can be upscaled from plot to field and regional scale. In addition such models are becoming increasingly important in the development of GHG accounting systems. There is a need to investjgate the applicability of such models to the major ecosystem types in Ireland. A literature review was carried out to evaluate the use of the RothC CENTURY DNDC and PaSim models for modeling soil organic carbon (SOC) stock changes in Irish grasslands (Chapter 2). RothC CENTURY and DNDC have simulated SOC stock changes in mineral soils under grassland arable and forest cover. PaSim has not been used similarly. Based on this review CENTURY and RothC are the most suitable models for simulating SOC stock changes in grassland soils in Ireland. Where assessment s of nitrous oxide emissions are to be carried out in tandem with SOC stock change investigations the DNDC model should be considered. The potential response to climate change of SOC stocks in two grassland sites in Ireland with contrasting soil and climatic conditions was assessed using the RothC CENTURY and DNDC models (Chapter 3). The future climate was simulated using regionally downscaled datasets for the period 2021-2060 for a range of Intergovernmental Panel on Climate Change emissions scenarios. All three models predicted a reduction in SOC stocks at the Cork site with variation between models and scenarios. The range of reduction of SOC was 1.9 to 7.4 t C ha-1 equivalent to a percent loss range of 1.4 to 5.4 %. At the Wexford site the CENTURY and DNDC models predicted small changes in SOC while RothC predicted losses of 2.3 - 4.4 t C ha-1 equivalent to a percent loss range of 2.9 to 5.7 %. Although these models should be tested at more sites RothC and CENTURY appear to be more suitable than DNDC for simulating future changes in soil carbon stocks in Irish soils. There is an urgent need to establish experiments which will provide data on long term changes in SOC stocks and provide a sound basis for further model comparisons and regional and national scale assessments. Suitable datasets relating to climate soils and land management should be collated and harmonized so that a GIS based platform for model upscaling can be developed and information gaps identified.

Grant Approved

�155,266.96

Research Hub

Natural Environment

Research Theme

Soils and Land-Use

Start Date

n/a

Initial Projected Completion Date

n/a